The invention relates to a device and method for dispensing flowable materials from flexible containers and, more particularly, to a device and method for more accurately, uniformly and rapidly heating/cooling a food product and for delivering the food product at a desired controlled temperature from a flexible container.
Heated or refrigerated dispensers for delivering liquid or semi-liquid food products are commonly used in foodservice restaurants, catering, convenience stores and other commercial or public food establishments. The known dispensers are usually adapted for receiving food bags in a housing and to deliver the food by using pumps and/or gravity forces to a dispensing area.
Food product, such as cheese sauces and the like, usually requires to be served at warm temperature to adapt to culinary habits and/or to improve the digestion of fat. Other food products are adapted to be stored at ambient such as UHT cream, sterilized salad dressing or pudding but request to be served at a refrigerated state. These food products are also usually low acid food which may be easily subjected to bacterial spoilage when opened, whereby heating or cooling permits to keep the food in safer bacteriological conditions. The products usually need to be stored in aseptically hermetic flexible packages such as pouches, which are opened at the time the product is dispensed. The problem is that the pouches are usually of relatively large size, in general of several kilograms, thus requiring a relatively long time before obtaining a controlled hot/cool temperature acceptable for serving.
One disadvantage of having a long heat-up/cooling-down time is that a fully warm/cool food bag may not be rapidly available when the demand for food exceeds the warming/cooling operation time for the new bag. Another disadvantage is when the bag is opened before the product reaches a sufficiently safe temperature level, i.e., about 60xc2x0 C. in the case of hot product or below 4-6xc2x0 C. for refrigerated products, the risk of bacterial contamination or spoilage seriously increases.
For instance, the American NSF standards require that potential hazardous food products having a pH level of 4.6 or less to be rethermalized; i.e., heated from refrigerated or ambient state to an elevated temperature of not less than 140xc2x0 F., must be capable of heating the food product to that temperature within four hours. For example, by using existing commercial equipment, the average heat-up time for large size pouches is of more than 2 hours, most often of more than 5 hours and sometimes of more than 10 hours before the center part of the pouch can reach an acceptable warm temperature of 60xc2x0 C. from ambient.
In order to meet with the regulations, prior solutions consisted in pre-warming the bag in a hot water bath or in microwave oven, then, transferring the preheated bag to the dispensing unit where the bag remains temperature controlled. However, this is not satisfactory as it requires to have an additional piece of equipment for heating available. A water bath is usually cumbursome and requires a long time to warm up. Microwave heating also suffers from non-homogeneous heating problems with formation of cold and hot spots in the food. It also requires manipulation and surveillance by the foodservice operators to transfer the food pouch from the microwave unit to the holding unit. Finally, it is required to invest in microwave ovens of sufficiently large capacity and of wide radiation fields to accommodate large size pouches.
Similarly, for sterilized food products that require to be served refrigerated, it is frequent that the foodservice operator cannot count on a refrigerating room for pre-cooling the food due to lack of space or for economical reasons.
U.S. Pat. No. 5,803,317 to Wheeler relates to a heated dispensing apparatus for dispensing products at elevated temperature which allows packaging of the product in a container, such as a flexible bag, with a discharge tube extending therefrom. The dispenser includes a receptacle with an outlet opening in the lower portion thereof and a pump adjacent to the outlet opening. A heater is provided for heating the food bag in the receptacle and the discharge tube passing through the pump and maintaining both the bag and the tube at a desired elevated temperature. The receptacle is arranged to accomodate the reception of so-called xe2x80x9cbag-in-boxxe2x80x9d type of package as illustrated in FIG. 1 of the patent. This type of package are disclosed in U.S. Pat. Nos. 3,173,579 and 4,796,788. The box portion of the xe2x80x9cbag-in-boxxe2x80x9d type package is not required for use with the dispensing device. The bag itself is usually a bulky flexible bag with a fitment protruding on one side of the bag. The bag is arranged in the receptacle so that only the side with the fitment is positioned adjacent a sloped heated bottom wall of the receptacle with the fitment of the bag passing through the outlet opening which ends or extends by a discharge tube. Due to the position of the bag in the receptacle, the thermal transfer from the receptacle to the bag remains relatively poor, thereby leading to excessive heat-up time when cold and large size bags are loaded for rethermalization. Furthermore, the heating pattern cannot be obtained uniformly within the product and a heat gradient is likely to form with the warmer side in contact with the receptacle and the colder side opposite. As a result, the food product may experience browning and darker spots, which consequently affect the quality and shorten the shelf life of the food product.
U.S. Pat. No 6,003,733 to wheeler notices the heating of the food product by pure conduction transfer as taught by former U.S. Pat. No. 5,803,317 does not always provide an optimal uniform heating and may make the internal and external receptacle surfaces extremely hot thereby increasing the difficulty of handling the dispenser. Therefore, it proposes to replace the conduction means by convection heating means using a rear heating assembly to continuously circulate heated air into the internal cavity around the receptacle for the bag to maintain the food product at elevated temperature. However, the time necessary for heating a large capacity bag from ambient to a temperature of serving remains a significant problem with such a device as well. A heating gradient is also likely to occur as the bag presents both heat sink zones and air contact zones of large surfaces due both to the type of bag and to the manner the bag rests in the receptacle.
U.S. Pat. No. 6,016,935 relates to a viscous food dispensing and heating/cooling assembly which is adapted to receive large food reservoirs of the xe2x80x9cbag-in-boxxe2x80x9d type in a manner similar to the previous patent references; the improvement consisting in a specific air flow circulation to heat both the reservoir and the discharge tube.
U.S. Pat. 6,056,157 to Gehl proposed a dispensing unit with a heated hopper which is sized to receive two superposed xe2x80x9cbag-in-boxxe2x80x9d type bags; a lower dispensing food bag resting flat along a bottom sloped wall with its fitment oriented horizontally and operatively connected to a dispensing unit and a second bag placed on top of the lower bag to serve as a weight for promoting gravity flow from the lower dispensing food bag and to precondition the second food bag. Due to the relatively thick material mass created by the superposition of two bulky bags, the time for heating the bag is very long. Similarly, more thermal energy is required for constantly maintaining the bags at warm temperature. The food will also experience a heat gradient with quick apparition of brown and dark spots. In this prior art device, a preheating compartment may be provided in the hopper to preheat a food bag more rapidly. The dispensing bag can then spread out in the hopper below the preheating compartment for dispensing purpose. The manner the bag spreads out in the hopper is similar to the previously discussed patents. Such heating and dispensing configuration has several shortcomings. Firstly, the heating of the dispensing bag is not optimized due to the spreading out of the bag along the sloped bottom wall and therefore is energy consuming. Secondly, the evacuation of food from the dispensing food bag is relatively poor despite the provision of the sloped geometry for supporting the dispensing bag. Thirdly, the preheating compartment is likely to provide a reduction of the heat-up time but not in a magnitude that can really be considered as a major advantage of the device. Fourthly, the hopper and its preheating compartment is configured to render the positioning and removal of the dispensing bag relatively uneasy in hot conditions because the preheating compartment partly obstructs the passage when the operator needs to have access to the dispensing bag. Fifthly, handling of hot bags in the device may create risks of bums for the operator, in particular when touching hot parts of the hopper.
German company Herman Roelofsen GmbH manufactures food dispensing units comprising a relatively wide box-shaped aluminum container adapted to receive a flexible food bag. The bag is loosely housed within the container and a bar inserted in two slots of the container hangs up the bag to avoid collapsing of the bag within the container. The container fits within a heating metal compartment of the unit which is heated by flexible heating devices. Due to heat loss in the transitions and air gaps from the heaters to the food, the dispensing unit has poor heating performance on large size bags with an heat-up time of more than 10 hours from ambient state for cheese sauce bags. Therefore, microwave preheating of the bag is required before the bag can be installed in the dispensing unit.
Therefore, one object of the invention is to provide a dispensing device that confers an improved heating/cooling output over the existing devices of the prior art, in particular, reduces the heat-up/cooling-down time significantly and is easy to hold the product at the desired controlled temperature while not being more energy consuming than existing equipment.
Another object of the invention is to provide a dispensing device, whereby uniform heating/cooling is promoted within the bag or pouch with no significant heat/cooling gradient, therefore, preventing from quality and safety issues and increasing the shelf life of the product when installed in the unit.
Another object of the invention is to ensure more continuity in delivering food product at a desirable controlled temperature; i.e., heated or refrigerated temperature, and convenience for the foodservice operator.
Another object of the invention is to provide a system which avoids having to control the temperature of the food in a separate unit such as to preheat/precool the food in a microwave oven/refrigerator.
Another object of the invention is to provide a dispensing configuration, whereby the product evacuation is improved with a minimum of non-dispensable residue left in the bag or pouch.
Another object of the invention is to improve the handling of the food container""s from an operator""s point of view while minimizing the operator""s manipulation and minimizing hazards such as risks of bums with the bag and/or hot parts of the device.
Therefore, the invention relates to a food dispensing device having an enhanced capacity for controlling the temperature of a flowable food product comprising:
a housing defining an interior cavity;
a first pair of opposed thermal conductive surfaces delimiting a spacing therebetween adapted for receiving a first pouch having two extensive walls; said thermal conductive surfaces being substantially oriented within the housing so that the pouch substantially remains in a standing position while the thermal conductive surfaces being arranged to intimately contact said extensive walls of the pouch;
means for controlling temperature of said first pair of opposed thermal conductive surfaces;
means adapted to operatively connect to the first pouch for selectively delivering portions of food from the first pouch.
In a preferred embodiment, the dispensing device further comprises at least a second pair of opposed thermal conductive surfaces delimiting a spacing therebetween adapted for receiving a second pouch having two extensive walls; said thermal conductive surfaces being substantially oriented within the housing so that the pouch substantially remains in a standing position while the thermal conductive surfaces being arranged to intimately contact said walls of the pouch.
Preferably, the spacing for receiving the pouch of the thermal conductive surfaces of the first pair and, even more preferably of the first and second pairs, is equal to or less than 40 mm, even preferably of about 35 mm or less. A limited spacing as defined allows the food product to spread along the heating surfaces regardless of the pouch capacity while eliminating the areas of higher thermal inertia in the food product. Such spacing has proved both to promote a rapid heat-up of the pouches and to require less energy for constantly maintaining the pouches at an elevated temperature. Therefore, it also contributes to more uniformly and accurately control the temperature of the food product with reduction of heat gradients. Consequently, it is made possible to eliminate the hot spots which normally create local browning of the food, thereby affecting its quality and shelf life. The temperature of the food product can also be maintained substantially constant over time, thereby similarly ensuring a longer shelf life. Although not expressly limited to large capacity pouches, the invention promotes a more efficient, accurate and rapid heating of the food product; i.e., in less than 2 hours from ambient, when the pouches contains more than 2.0 Kg, and even more than 2.5 Kg of food product.
Preferably, the at least first and second pairs of opposed thermal conductive surfaces are parts of removable cassettes which may further comprise a bottom surface and an outlet opening, preferably arranged in the bottom surface, to allow a discharge tube of the flexible pouch to pass therethrough. The cassettes are removable from the housing, thereby facilitating the exchange of cassettes for replacement of the pouch by a new pouch and/or to change the relative location of the cassettes within the housing so that one cassette which was held in a preheating mode may be installed in a dispensing mode and inversely.
In a preferred mode, at least two identical cassettes are provided within the housing to offer the possibility to have a first dispensing cassette and a second preheating cassette; the dispensing cassette being removable to be replaced by the preheated cassette at any required time after the food in the preheated cassette has reached an acceptable elevated temperature within the housing. Preferably, the first cassette is positioned in the housing in a position adapted to a dispensing mode; e.g., whereby the outlet opening of the cassette may preferably substantially aligned with the valve means. The first cassette is also constantly maintained at the right elevated temperature while dispensing of the food. Preferably, the second cassette is positioned in the housing in a preheating mode where the outlet opening of the cassette is substantially offset with respect to the valve means. Still in a preferred mode, the first and second cassettes are configured in parallel in the housing to permit one cassette to be replaced by the other more easily. The cassettes may preferably be removable from the housing by sliding motion of the cassette(s) in a primary direction after opening of the housing. It is meant that the same modularity approach can be applied for cooling of the pouch; i.e., using dispensing refrigerated cassette(s) and pre-refrigerating cassette(s) which can be exchanged one by the other to ensure a continuity in the supply of refrigerated product and, therefore, more convenience to the foodservice operator.
For food that needs to be served warm, the means for controlling the temperature of the thermal conductive surfaces may preferably be heating means to heat the product in the pouches. Importantly, heating is provided to the thermal conductive surfaces so that the thermal conductive surfaces serve as primary conductive heaters for the pouch. For that, the heating means may be resistive heating elements directly coupled to said opposed thermal conductive surfaces and/or air forced convection means adapted to provide hot air substantially surrounding the thermal conductive surfaces.
In an embodiment, the thermal conductive surfaces may comprise at least a first and second resistive heating sets which are capable of being selectively operated to provide at least two different power modes. In this way, it is made possible to accomplish a two-mode heating of the food product; i.e., a first heat-up mode whereby the food can heat up fastly by receiving a higher heating power and a second holding mode, whereby the food can be maintained at the desired elevated temperature by receiving a comparatively lower heating power. The two modes may be carried out by selectively operating the first and second resistive sets using suitable controlling and thermostatic means.
The heating means may also pass through the valve means to maintain the product at elevated temperature in the tubing of the pouch as already taught in U.S. Pat. No. 5,803,317. As taking part of the uniform and rapid heating capacity of the device of the invention, the convection means preferably comprises a series of flow paths which distribute hot air along the thermal conductive surfaces. Of course, it may be possible to combine resistive heating means and convection means in the same device.
In another aspect, the invention relates to a dispensing device for dispensing flowable food product comprising:
a housing defining an interior cavity;
at least one pair of removable identical cassettes within the housing; each being adapted for receiving a pouch containing food; said cassettes comprising pairs of opposed thermal conductive surfaces wherein the surfaces delimit together a spacing adapted to receive a pouch;
means for controlling the temperature of said at least pair of cassettes; wherein the cassettes are interchangeable.
Another aspect of the invention relates to a dispensing device for rapidly and efficiently heating/cooling a flowable food product whereby removable cassettes are provided for receiving a pouch containing food; the cassettes comprising pairs of opposed thermal conductive surfaces wherein the surfaces delimit together a spacing adapted to contact a pouch and means for controlling the temperature of said at least pair of cassettes.
Another aspect of the invention relates to a method for rapidly heating/cooling and delivering a flowable food comprising:
providing a pouch comprising two extensive walls connected together by a plurality of peripheral edge portions to form a closed interior for the food of relatively narrow profile; and a fitment to deliver the flow of food through an outlet; said fitment being sealed across one edge portion of the pouch;
positioning said pouch between two opposed vertically oriented thermal conductive surfaces delimiting a spacing therebetween adapted for receiving the pouch with the extensive walls intimately contacting the thermal conductive surfaces;
controlling temperature of the food contained in the pouch by conduction transfer from the two thermal conductive surfaces to the pouch;
providing valve means to selectively control the flow of food from the pouch.
In another aspect, the invention relates to a method for ensuring a steady supplying in warm food product within a dispensing device comprising:
providing a pair of cassettes containing food within a container; said cassettes being interchangeable within the dispensing device;
providing heat to each of said cassettes to warm the food product;
dispensing food from one of said heated cassettes while holding the other cassette warm.